Recent content by mune

what about the flow work? the air molecules which flow from A to B have some KE right? The KE will change into thermal E after the valved is closed?

what if they started with the same temperature, other condition remains the same? assume the values are gage pressure values(but does make any difference?)

Hi all, Let's say we have 2 closed cylinders A and B, same volume, containing air inside. Two cylinders are connected to each other with a tube, with valve. Initially the valve is closed. cylinder A: P=100 Pa, T= 350 k. cylinder B: P=50 Pa, T= 300 k now if the valve is opened, and closed when...

thanks. you clear my head:smile:

can I say dW=Vdp? as the work done is the area under under the PV-curve, we also can use VdP to find the area right? just like finding area under a curve by integrating xdy.

will go to see it after a few minutes. thanks.

1. what is the physical interpretation of enthalpy and entropy? enthalpy, U+PV, is the heat can be used to do work and entropy, dQ/T is a measure of randomness. but i still don't understand, what does a large change in enthalpy and a small change in enthalpy means physically? same for entropy...

thanks everyone. I can understand d(U+PV) = dU + PdV + VdP, but why dQ is not equal to d(U + PV)? Q= U + W => dQ = d(U + PV), where W=PV? but dH = d(U + PV) makes sense to me too!

Hi. Could anyone clear my doubts? U_2-U_1= C_v(T_2 - T_1) and H_2 - H_1 = C_p (T_2 - T_1): Do these two equations always valid, regardless the process is adiabatic, isobaric ect? At the first place, I thought one works only for isobaric and another for isochloric, because I see C_v and...

Hi guys, I need help on thermodynamics: 1. what is the physical interpretation of enthalpy and entropy? 2. in an open system, change in total energy = change in enthalpy? 3. every reversible process must be adiabatic? 4. what does clausius inequality means? 5. Q-W=U is for closed...

thanks siddharth. You are right, for the process to be isothermal, n has to be equal to 1. I checked my textbook again, and I realized I missed that part last time. Today I just learned that PV^n = constant is also called path equation, all process in thermodynamics can be represent by this...

Hi guys,I have some questions about this equation: P.V^(gamma) = constant, gamma = C_p / C_v Is it only valid for a adiabatic process, plus ideal gas? I thought it was at the first place, as I saw its derivation uses adiabatic properties(dQ=0) and assumes the gas is ideal (PV=mRT). But when I...

thank you everyone :smile: sorry that I didn't explain my question clearly. Anyway, Gib Z and HallsofIvy know what I mean :cool: but thanks d_leet too, I have learned a way to prove from your post.

it is not a trick question, nor a very highly theoretical question.

let's say we are given a function y=f(x), what is relationship between it and y^2 =f(x)? for example, if y=f(x) have a maximum point at (a,b), will y^2=f(x) have a maximum point at(a,b) too? i hope i make my question clear.:smile: